Language Delay and Externalizing Problems in Preschool Age: A Prospective Cohort Study.

Area of Science:

• Developmental Psychology
• Child Psychiatry
• Linguistics

Background:

• Language delay and externalizing problems like inattention and aggression frequently co-occur in preschool children.
• The precise direction of causality between language delay and these behavioral issues remains incompletely understood.

Purpose of the Study:

• To investigate the causal relationship between language delay and inattention.
• To examine the causal relationship between language delay and aggression in young children.

Main Methods:

• Utilized autoregressive fixed effects models on longitudinal data from 25,474 children (ages 1.5-5 years) in the Norwegian Mother and Child Cohort Study (MoBa).
• Modeled the direction of causality between language delay and inattention, and between language delay and aggression.

Main Results:

• The relationship between language delay and inattention appears reciprocal, with inattention significantly influencing language delay (b=0.19, p=0.03), while the effect of language delay on inattention was non-significant (b=0.12, p=0.06) after accounting for common factors.
• Language delay was found to significantly cause aggression (b=0.12, p<0.02), with the entire association explained by this direction of effect.

Conclusions:

• Language delay is best understood as a potential cause of aggression in preschool children.
• Inattention may influence language delay, with common factors playing a role, suggesting language delay is partly an epiphenomenon of inattention.
• Findings highlight the importance of addressing language delay to prevent co-occurring externalizing problems and inform targeted interventions.